In order to decrease undesirable exhaust emissions and improve performance, there has been a trend in the fuel injection industry to decouple the injection timing from the crankshaft position of the engine. In most instances, this is accomplished by incorporating an electronic control valve that is controlled in its activation and deactivation by a conventional electronic control module. Because of the relatively extreme environments encountered within fuel injectors, these control valves are typically made up of a plurality of hardened metallic components that are machined and fitted to relatively tight tolerances.
In some instances, fuel injector control valves include an elongated valve member that moves between a pair of opposing conically shaped valve seats. Because the valve member is trapped between the opposing valve seats, such a valve assembly must necessarily include at least three separate components; a first valve body component having a machined upper seat is mated to a second body component having a lower valve seat after the elongated valve member is positioned between the two seats. In order to reduce stress from side forces and ensure proper sealing when the valve member is seated against the upper or lower conically shaped valve seats, it is typically necessary that the centerlines of the valve seats and that of the valve member be as concentrically aligned as possible. Because of the current limitations in machining technology and the necessity to have some tolerancing bounds for any mass produced multi-component device, there is always room for improving the concentric alignment of multi-component valve assemblies.
There are currently several methods known in the art for aligning valve components. Among these are the use of outer alignment rings and/or the use of internal alignment dowels. While both of these methods can be utilized to successfully align components in a valve assembly, they are often cumbersome and usually require very close attention to tolerancing details.
The present invention is directed to overcoming these and other problems associated with concentrically aligning components in valve assemblies.